1. Field of the Invention
The present invention relates to supplying carders, in which fibrous flock material is worked by a series of surfaces which are provided with a multiplicity of tips, by which the fibrous material is opened up into the form of individual fibers, the particles of dirt are eliminated, the fibers are mingled with one another, and a strip of non-twisted fibers is formed, to be conveyed to the successive processing stages.
2. Discussion of Background
In its most general outlines, the operation of supply to carders of the cotton-industry type is carried out according to the significant aspects of the diagram illustrated in FIG. 1. The light-coloured arrows indicate the flow of flock fibers,whereas the dark arrows indicate the flow of the conveying and control air.
The untreated material 1 is obtained in general from a opener, not shown in the figure, and includes flock fibers. The supply device includes a vertical silo, which is subdivided into two chambers, one above the other, between which there is interposed a set of rollers which regulate the descending flow, and carry out initial breaking and separation of the material. This fibrous material is conveyed by means of pneumatic transport in an air current, and is accumulated in the end part 2 of the descending duct or upper chamber 3 for intake of the fibers. The transport air is discharged from the apertures 4; as the fibrous material is deposited in the end part 2, it covers these holes, and increases the pressure in the duct 1a. Monitoring of the differential pressure value, or load loss, in the upper duct, makes it possible to detect the level of filling of the upper chamber in the end part 2. On the basis of the level of filling of the chamber, there is regulation of the conveyance of flock fibers from the preceding set of openers. If the carding unit consists of several carders in parallel, the flow of fibers, conveyed by the opener unit upstream to the carder downstream, is preferably distributed to the carders which have their ducts 3 least filled, and which thus provide a lower load loss relative to the flow of fibers.
Downstream from the end part 2, there is disposed the supply cylinder or roller 5, which supplies the flock fibers to the breaker cylinder or roller 6, which carries out the breaking of the material. The two cylinders operate with simultaneous rotation, in order to transfer the material in,o the duct 7 beneath.
According to the known art, the supply roller 5 is actuated at a variable speed of rotation, and is produced lobed, or is provided with a covering with saw teeth. In general, the saw-tooth covering is produced with positive angling, i.e. with the steepest edge facing in the direction of feed, with the effect of thrusting the flock fiber towards the tips of the breaker cylinder 6.
The supply roller 5 works facing the wall 2' of the end part 2 of the duct 3 for intake of the fibers 1, in order to create between the roller and the wall a gap 2" for passage of the fibers.
The breaker roller 6 works at a constant linear speed, and is provided with a series of tips or needles 8, which are spaced from one another. The breaker roller 6 works facing the curved wall 9 which surrounds it, in order to create a second gap 9' for passage of the fibers.
The air current in order to maintain the pressure in the lower chamber 10 at the end of the duct 7 is supplied by a blower 11, which provides a flow of air which is tangential relative to the output of the fibers from the breaker cylinder 6, and is then discharged from the holes 12. In the duct 7' there is installed a pressure switch, which controls the speed of rotation of the roller 5, such as to regulate the density of the fibers which are contained in the lower chamber 10, and form the mat supplied to the carder.
The base of the second descending duct 7 is equivalent to conventional storage of fibers in a silo, in which the density of the fibers is controlled and regulated by pneumatic effect. The set of discharge cylinders or lobed rollers 13, which rotate at a controlled speed, in order to regulate the flow of fibers, discharges the fibers onto a slide 14, which supplies the fibers in the form of a mat 15 to the carder.
The transverse dimension of the mat supplied depends on that of the processing cylinders of the carder; for carders of the cotton-industry type, this transverse dimension is in general between 0.7 and 1.5 m, depending on the models.
The supply system according to the known art described hitherto has some problems. Significant amongst these problems is the inefficient opening action by the system, on the flock fibrous material supplied, and particularly when operation takes place with a high level of hourly production of the carder. This reduced efficiency of opening of the flock is caused by poor action of penetration of the tips of the breaker roller, which is carried out only on the fibers which are held between the roller and the wall which surrounds it, which acts as a supply table for the silo. There is also premature wear of the tips of the breaker roller, which must be replaced at brief intervals.
A further disadvantage consists of the formation of neps, or tangles of fibers caused by curling of the fibers as a result of sliding of the latter on the wall 2' opposite the roller 5.